Boron-doped Carbon Nanotubes Research Articles

Topology of boron substitutional defects in single-walled carbon nanotubes: A first-principles study

This is a theoretical study of boron-doped single-walled carbon nanotubes. The same topology of primitive nanodomains, located at different positions on single-walled carbon nanotubes, leads to different electronic band structures. We propose a ϕ term. Density functional theory was corrected for van der Waals interactions and used to carry out the periodic boundary condition geometry optimization, where boron formed the topologies of primitive nanodomains. The calculated bulk structure and local structure spectroscopic parameters can be used for comparison with experimental results to confirm the theoretical models.

Preparation of a new B-CNTs/PSSF composite catalyst for catalytic wet peroxide oxidation of phenol in structured fixed bed

A new structured catalyst consisting of boron-doped carbon nanotubes growing directly on paper-like stainless steel fibers support (B-CNTs/PSSF) was developed for continuous catalytic wet peroxide oxidation (CWPO) of phenol in a structured fixed bed. Firstly, B-CNTs/PSSF was synthesized by chemical vapor deposition (CVD) with phenyboronic acid as a single precursor and CNTs/PSSF was prepared with camphor for comparison. Secondly, the effects of different deposition temperatures, deposition times, and phenylboronic acid dosages on the morphology and properties of B-CNTs were investigated, respectively. The results verified that under the conditions of deposition temperature of 750 °C, deposition time of 20 min, and phenylboronic acid dosage of 2 g, the B-CNTs/PSSF composite catalyst with uniform growth density, wavy and kinked morphology, abundant oxygen-containing functional groups and defect sites, and boron-doped content of 2.96% was successfully prepared. Then, the performance of B-CNTs/PSSF for continuous CWPO of phenol was evaluated. Catalytic results revealed that the B-CNTs/PSSF showed excellent catalytic activity in phenol degradation within 7 h (phenol conversion reached about 100% and total organic carbon (TOC) conversion was up to 68%). In contrast, the average phenol and TOC conversion of CNTs/PSSF were about 75% and 35%, respectively. It indicated that boron doping endowed CNTs with higher catalytic activity.

Thermoelectric Power Factor of Boron‐Doped Carbon Nanotubes Reinforced Cementitious Composites

In recent years, fossil fuel emissions and human activities have generated a lot of heat energy, causing environmental temperatures to rise. Thermoelectric cementitious composites that use temperature difference power generation to achieve the transformation of thermal and electrical energy can achieve a reduction in urban environmental temperature and alleviate resource depletion. However, the low thermoelectric conversion efficiency at this stage restricts its development. Herein, boron‐doped carbon nanotubes (B‐CNTs) are proposed to improve the thermoelectric properties of cement materials by doping boron into carbon nanotubes through the thermal diffusion method. At H3BO3: CNTs = 1:4, the synthesized B‐CNTs improve the Seebeck coefficient, which is mainly due to the increase in defect content and the appearance of additional phases around the Fermi energy level, leading to enhanced thermoelectric properties due to the increase in carrier scattering intensity. The thermoelectric optimum of the cement matrix composite with 7.0 wt% B‐CNTs content is 1.1 × 10−4, which is three times higher than that of the undoped carbon nanotube. This article provides a research idea to modify the thermoelectric properties of the material by doping the carbon material.

Adsorption and diffusion of sodium on boron-doped carbon nanotube

The first principles have been performed to investigated the performance of the boron-doped (B-doped) carbon nanotube for sodium-ion batteries. The Na adsorption energies at H1 and B1 sites are -2.821 eV and -2.523 eV, which have decreased by 0.985 and 0.846 eV as compared with pure CNT, respectively. The results indicate that B-doped CNT is beneficial for Na adsorption. The Na diffusing between two hollow sites across the TC1 and B1 sites shows low barriers of 0.309 eV. Additionally, the projected density of states (PDOS) shows that B-doped CNT exhibits metallicity and non-magnetic properties with Na adsorption, which is beneficial for electron transfer. The PDOS move towards higher energy levels, which is beneficial to enhance conductivity. These results suggest that B-doped CNT shows high performance as anode for sodium-ion batteries.

Computational and theoretical study of B-doped achiral single-walled carbon nanotubes: A nonresonant polarized Raman analysis

Tailoring the unique properties of carbon nanotubes should be studied. However, chemical doping by incorporation of boron atoms into carbon nanotubes (CNTs) has been examined as a powerful tool which provides various advantages. In this paper, we review several recent researches by which to dope carbon nanotubes by boron atoms into the sp2 carbon lattice, the properties induced by boron doping, and promising applications of this type of doping nanomaterials. We envisage that intrinsic boron doping will accelerate both scientific and industrial developments in the area of CNTs and nanotechnology in a later researches. Furthermore, the calculations of the polarized Raman active modes in boron-doped achiral single-walled carbon nanotubes are performed in the framework of the force constants model. Moreover, The spectral moment’s method was used in order to calculate the nonresonant Raman spectra for systems contain several atoms, it is shown that a powerful tool. The variations of the Raman spectra as a function of the rate doping of boron atoms are identified and the relative intensity ratio between Raman active modes of D and G bands has been analyzed. Raman spectroscopy analysis reveals mathematical expressions, it was derived to describe the dependence of the Radial Breathing Modes (RBM) with the diameter and the B-doping rate. It is shown that the diameter scale in Kataura’s plot must be converted into in order to directly compare to the experimental Raman spectra. Such conversion must be performed by using the relation ωRBM=218−1,2τD. Once this adjustment is done, one is ready to associate each pair (ωRBM,τ) to a specific (n, m) if the ωRBM values are well known. For example the RBM modes at 165 cm−1 and 133 cm−1 are assigned to the single walled carbon nanotube (10,10) and BC3 nanotube (5,5) respectively. The results of this work provide the (n, m) dependence of the RBM of SBCNTs, it gives good benchmark for performing (n,m) assignment of doped SWCNTs.

The effect of boron-doped carbon nanotubes blended with active layers in achieving high-efficiency polymer solar cells and X-ray detectors

Polymer solar cells (PSCs) usually offer inferior power conversion efficiency (PCE), lower open-circuit voltage (Voc), and inefficient charge extraction abilities. We studied boron-doped carbon nanotubes (B-CNTs) as the third active layer (AL) component to improve the PCE and Voc, due to their tunable work function, superior conductivity, and transport behavior. A novel arc discharge (AD) method produced B-CNTs without any residual catalysts. This work utilized PBDB-T: ITIC as the initial AL to prepare PSCs and X-ray detectors with glass/ITO/PEDOT: PSS/AL/LiF/Al structure. The excitation effects of PSC and X-ray detector devices based on ALs embedded with different amounts of B-CNTs were also studied. The derived outcomes revealed a PCE of 10.21 % for the constructed PSC with 3 wt% of B-CNTs blended AL. Furthermore, the fabricated X-ray photodetector with 3 wt% of B-CNTs obtained an excellent sensitivity of 2.49 mA/Gy·cm2. These results show that B-CNTs can act as both an exciton dissociation center and a charge transfer channel, promoting charge separation and transport in the AL.

Highly exposed NiFeOx nanoclusters supported on boron doped carbon nanotubes for electrocatalytic oxygen evolution reaction

The development of efficient and cost-effective electrocatalysts for oxygen evolution reaction (OER) is crucial for the overall water splitting. Herein, we prepared a highly exposed NiFeOx ultra-small nanoclusters supported on boron-doped carbon nonotubes catalyst, which achieves a 10 mA/cm2 anodic current density at a low overpotential of 213 mV and the Tafel slope of 52 mV/dec in 1.0 mol/L KOH, superior to the pristine NiFeOx-CNTs and other state-of-the-art OER catalysts in alkaline media. A combination study (XPS, sXAS and XAFS) verifies that the local atomic structure of Ni and Fe atoms in the nanoclusters are similar to NiO and Fe2O3, respectively, and the B atoms which are doped into the crystal lattice of CNTs leads to the optimization of Ni 3d eg orbitals. Furthermore, in-situ X-ray absorption spectroscopies reveal that the high valence state of Ni atoms are served as the real active sites. This work highlights that the precise control of highly exposed multicomponent nanocluster catalysts paves a new way for designing highly efficient catalysts at the atomic scale.

Defect-rich boron doped carbon nanotubes as an electrocatalyst for hybrid Li–air batteries

BC3NTs with topological defects improve the performance of hybrid lithium–air batteries, conducive to the ORR and OER.

Mass transfer analysis of boron-doped carbon nanotube cathodes for dual-electrolyte lithium-air batteries.

Dual-electrolyte Li-air batteries (LABs) have the advantages of high specific energy density and low overpotential, but the mass transfer mechanism is still unclear. Mass transfer is essential to battery performance. To improve the mass transfer capability of the positive electrode, this research studied the effect of boron (B)-doped carbon nanotubes (BC3NTs) with different amounts of defects as positive electrodes. Deep discharge results showed that the discharge voltage platform of BC3NTs was higher than that of CNTs, and the more defects, the higher the discharge voltage platform. The electrochemical impedance spectroscopy (EIS) results also showed that the more defects, the smaller the charge transfer resistance. As the discharge current density increased, the discharge voltage platform decreased gradually. Traditional molecular dynamics calculation results showed that the topological defects caused by BC3NTs reduced the Li+ and O2 diffusion energy barriers from the sidewalls from 4.5 eV to 1.65 eV and 4.94 eV to 0.11 eV, respectively. The diffusion capabilities of Li+ and O2 in BC3NTs were improved, and at the same concentration, the diffusion coefficients of Li+ and O2 increase to 3.0 × 10-9 m2 s-1 and 0.415 × 10-9 m2 s-1, respectively. The radial distribution function results showed that the larger the topological defect ring was, the greater the probability of finding Li+ and O2 near the electrode. In summary, the defects produced by BC3NTs were conducive to mass transfer, which could reduce polarization and impedance, and improve battery performance.

Synthesis of boron-doped carbon nanotubes by thermocatalytic decomposition of ethanol using a floating catalyst chemical vapor deposition method: kinetic study

The effect of different reaction parameters helped in understanding the structure–property relationship in B-doped CNTs. A plausible reaction kinetic model and a reaction mechanism were proposed for the FCCVD synthesis of BCNTs.

The Effect of Boron-Doped Carbon Nanotubes Blended Active Layer on Achieving High-Efficiency Polymer Solar Cells and X-Ray Detectors

The Effect of Boron-Doped Carbon Nanotubes Blended Active Layer on Achieving High-Efficiency Polymer Solar Cells and X-Ray Detectors

Hydrogen storage in boron-doped carbon nanotubes: Effect of dopant concentration

Boron-doped carbon nanotubes (BCNTs) with varying B content (0–8 at%) were prepared by thermo-catalytic decomposition of ethanol in presence of boric acid at 1073 K. It was observed that hydrogen adsorption capacity improved to a critical B content of 3.86 at% and then decreased. Maximum hydrogen adsorption was found to be 0.497 wt% at 273 K and 16 bar with 3.86 at% of boron doping in CNTs. With the help of transmission electron microscopy, X-ray photoelectron spectroscopy, and Raman spectroscopy, it was found that in addition to dopant concentration, dopant bonding with carbon structures, crystallinity and defects play pivotal roles in determining the extent of hydrogen adsorption by BCNTs. The thermogravimetric studies revealed the oxidation stability of the BCNTs. The hydrogen adsorption kinetics was found to follow the pseudo-second-order model. The rate constant value was minimum for the BCNT with the highest hydrogen storage capacity.

Boron-doped helical carbon nanotubes as active supercapacitor cathode materials: preparation and electrochemical properties

Boron-doped helical carbon nanotubes as active supercapacitor cathode materials: preparation and electrochemical properties

Boron-doped helical carbon nanotubes: lightweight and efficient microwave absorbers

Boron-doped helical carbon nanotubes: lightweight and efficient microwave absorbers

Effective defect generation and dual reaction pathways for phenol degradation on boron-doped carbon nanotubes

ABSTRACT A new type of metal-free catalyst was successfully prepared by doping boron (B) in the carbon nanotube. The catalyst had 99.4% removal of phenol in 60 min at pH 7 by activating peroxymonosulfate (PMS). In order to explore the origin of the high catalytic activity, the samples were characterized by Raman and electron paramagnetic resonance (EPR), and the reactive oxygen species (ROS) in the process of catalytic degradation were investigated. The Raman results showed that the defect sites increased after doping, which indicated that the B doping increases the active sites on the surface of the carbon nanotubes. Identification experiments of ROS found that not only hydroxyl radicals (·OH) and sulfate radical (SO4 −•), but also singlet oxygen (1O2) exist in the system. The presence of multiple free radicals indicated the existence of free radical reaction pathway, and the presence of 1O2 confirmed the existence of non-radical reaction pathway. These results indicated that there were dual reaction pathways for the activation of persulfate by B-doped carbon nanotubes, which was the intrinsic nature for the high catalytic activity of the system.

Regulating the interfacial behavior of carbon nanotubes for fast lithium storage

Carbon nanotubes (CNTs) have been recognized as a versatile platform to integrating with various electroactive materials for boosting the comprehensive electrochemical performance. However, CNTs with distinct interfacial characters may play different roles in the subsequent lithiation/delithiation process. Accordingly, systematically engineering the interface of CNTs on the lithium storage behavior is of fundamental significance but remains rare. Herein, the lithium storage performance of boron-doped carbon nanotubes (B-CNT), acid activated carbon nanotubes (aCNT) and commercial carbon nanotubes (CNT) have been systematically studied. We demonstrate that the B-CNT features as a prominent fast charging anode in terms of excellent rate performance and long cycling stability at large current density (an average Coulombic efficiency of 99.8% can be achieved at a high current density of 10 A g−1). The electrochemical kinetic analyses indicate pseudo-capacitance dominated mechanism of B-CNT leads to faster electron/ion transport kinetics. In-depth theoretical simulation suggests that moderate lithium adsorption energy of B-CNT is important to balance the adsorption and release of Li ions, thus resulting fast lithium storage capacity. As a verification, the composite electrode with B-CNT as additive and silicon as anode material also shows outstanding rate performance. Therefore, these basic researches can provide valuable guidance for reasonable design of CNTs-based composite electrode materials toward high-rate batteries.

Insights into active species of ultrafine iridium oxide nanoparticle electrocatalysts in hydrogen/oxygen evolution reactions

Heteroatom doping is a potent strategy to regulate electronic structures and improve electrocatalytic performances, which has been extensively applied in fabricating carbon-based composite catalysts. Here, we report an ultrafine iridium oxide supported on boron-doped carbon nanotubes with rich defects for high-efficiency hydrogen/oxygen evolution reactions and overall water splitting at all pH values. Theoretical study shows that the excellent OER and HER activities of ultrafine IrO2 nanoparticles can be attributed to their enhanced redox abilities comparing to those of bulk IrO2 catalysts. Under OER conditions, the O-excessive surface of ultra-fine IrO2 nanoparticles weakens the binding strengths of oxygenated species, leading to enhanced OER activity. Under HER conditions, the surface of the IrO2 nanoparticle will be reduced to an intermediate state between Ir oxide and Ir metal, which greatly enhances the H binding energy and thus improves HER activity (even higher than Pt(111)).

Insights into the peroxomonosulfate activation on boron-doped carbon nanotubes: Performance and mechanisms

Preparation of carbonaceous catalysts by doping with boron (B) is one of the most promising strategies for substitution of toxic transition metal catalysts in advanced oxidation processes. This study was dedicated to reveal the intrinsic structure-performance relationship of peroxomonosulfate (PMS) activation by B-doped carbon nanotubes toward catalytic oxidation of pollutants. Performance tests showed the catalyst realized more than 95% phenol removal at pH 7 in 1 h and 69.4% total organic carbon removal. The catalysts were characterized using scanning electron microscopy (SEM), transmission electron microscope (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). Characterization results indicated that the topography of carbon nanotube was not significantly changed after B doped, while the defect sites increased from 1.05 to 1.23. The newly formed active sites may be presented in the form of C3B, CBO2 and CBO3, and reactive oxygen species (ROS) including OH, SO4−•, O2−• and 1O2 might be generated after activation by the active sites. Furthermore, B-MWNT-PMS∗ was also be detected by In-situ Raman, confirming the non-radical pathway and electron transfer mechanism. Beside of phenol, the reaction system of B-MWNT/PMS also can remove methylene blue, bisphenol S and diuron at pH = 7, confirming the universality and promising of this advanced oxidation technology.

Tailorable boron-doped carbon nanotubes as high-efficiency counter electrodes for quantum dot sensitized solar cells

1. Tunable BCNTs are prepared by the pre-oxidation strategy. 2. B-Doped CNTs exhibit excellent activity for Sn2− reduction. 3. The QDSSC based on CdS/CdSe QDs and BCNT1 shows a PCE of 4.55% under one sunlight illumination.

Bimetallic MnCo alloy nanoparticles decorated boron-doped carbon nanotubes as an active and durable electrode for supercapacitor

Abstract The demand for low-cost and high-performance energy storage supercapacitors is continuously promoting as a result of the rapid development of portable electric vehicles and electronic devices. Here, a high-performance MnCo alloy nanoparticles decorated boron-doped carbon nanotubes (MnCo–B/CNTs) electrode was obtained by a facile heteroatom hydrothermal and subsequent liquid-phase reduction methods, which yields improved performance for supercapacitor. In this process, boron doping led to extra oxygen graft into carbon surface, leading to the improved durability and wettability of the fabricated carbon-based electrodes, which presented both increased capacitances and rate capability due to electrolyte ion penetration and interactions with carbon surface. In addition, boron doping led to smaller size and higher dispersion of MnCo nanoparticles, facilitating more metallic alloy and new electroactive sites formation and promoting supercapacitive activity, which was attributed to increased MnCo alloy nucleation rate with boron-doped, electron donation from boron to alloy, and extra chemisorption sites. The constructed electrode exhibited all-round performance improvements of specific capacitance (1175 F g−1 at 0.5 A g−1) and capacitance retention (94.48% at a current density of 20 A g−1 after 5000 cycles), providing a novel insight for designing high performance supercapacitors.